STEELMATE DIY Wireless CIG Plug TPMS With 4 External Valve-cap Sensors Tire Pressure Monitoring System Model (20-50 Psi) Fit for Android / iPod /iPhone / iPad DIY installation & Anti-Theft Valve-cap Replaceable Batteries Sensors Model Unique Design DIY TPMS for Convenient Smart phone Monitor! Real-Time individual tire data on iPhone/iPod Touch/iPad/Android Smart phone Specific Bluetooth Channel, work with STEELMATE Engine Lock for Smart phone simultaneously Convertible Bar/ Psi Pressure Units Monitoring Pressure Range for reference: 0-3.5Bar /0-50Psi